Watch for rattlers, Heavy clothing is a good idea. Its the law, when you shoot antelope you get in a good position you have to set or kneel in cactus.
Most people over estimate the range to antelope. They are small, plus often you find them in tall grass, making them look smaller or farther away.
For some reason, range finders don't work very well on the prairie. I like using Mil Dots, they seem to be more accurate.
The average antelope is about 14.5 inches from the bottom of its stomach to the top of its back. The Vital area is about 8-9 inches. So if the goat is 1 mil dot, its about 417 yards.
I like to sight my rifle in for a max point blank range where as if I aim to the center of the vital area, I'm not over 4 inches high or 4 inches low. The gun/ammo combination I use that would be about 350 yards, or the animal (top to bottom of stomack) is about 1.2 mils.
Your gun/ammo may be different, that you have to figure out.
NEVER shoot at a running antelope. Those suckers can run fast, but at 200 yards or so you can't tell if they are running 30 or 45 miles an hour. Figure you bullets time of flight, to that distance. Then figure the speed of the goat, (MPH X 1.47 = fps) you'll see there is a huge difference of the amount of lead you need.
Meaning lots of wounded critters running off to die.
Also if you shoot at an antelope and they take off running, don't assume you miss. Watch them, they can run a long ways after their lungs are totally blown out.
Plus often when hit, they run like there is nothing wrong with them.
The one I shot last year did this. I shot, it booked, and I figured I missed. I watched it thinking it might stop and I would get another change, but instead, it ran about 100 yards and did a summersault.
When I dressed it out, I found both lungs looked like a pile of coffee grounds.
Again watch for rattlers, a couple years ago I got behind a little hill trying to crawl up on some antelope and found my self nose to nose with a rattler. Needless to say I forgot about the goats and dispatched the snake with a little J Frame I carried in my pocket.
Also take some tweezers, cause you're going to be picking out cactus. That's a given.
Weather is going to range from cool in the morning to warm later in the day.
And expect to shoot in wind. I does get drafty in Wyoming every now and then. Depending on the round you're using, if you keep your shooting to under 300 yards, wind isn't gonna get you that much but it will get you.
You should know how to read wind. An example, a 15 MPH Full Value wind, my 130 gr 270 Win. drifts about 3 MOA at 300 yards, that's 9 inches.
I suggest camping in the field. I live a short distance from where I hunt, but I love laying out on the prairie at night watching the stars and listening to coyotes. To me that's the best part about antelope hunting.